
package com.onpositive.mapper.newwizard;

import org.eclipse.swt.SWT;
import org.eclipse.swt.accessibility.AccessibleAdapter;
import org.eclipse.swt.accessibility.AccessibleEvent;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Caret;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.Widget;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.jface.resource.JFaceResources;

/**
 * Utility class to simplify access to some SWT resources.
 */
public class SWTUtil {

    /**
     * The default visible item count for {@link Combo}s.
     * Workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=245569 .
     *
     * @see Combo#setVisibleItemCount(int)
     *
     * @since 3.5
     */
    public static final int COMBO_VISIBLE_ITEM_COUNT = 30;

    /**
     * Returns the standard display to be used. The method first checks, if
     * the thread calling this method has an associated display. If so, this
     * display is returned. Otherwise the method returns the default display.
     * @return returns the standard display to be used
     */
    public static Display getStandardDisplay() {
        Display display;
        display = Display.getCurrent();
        if (display == null)
            display = Display.getDefault();
        return display;
    }

    /**
     * Returns the shell for the given widget. If the widget doesn't represent
     * a SWT object that manage a shell, <code>null</code> is returned.
     * @param widget the widget
     *
     * @return the shell for the given widget
     */
    public static Shell getShell(Widget widget) {
        if (widget instanceof  Control)
            return ((Control) widget).getShell();
        if (widget instanceof  Caret)
            return ((Caret) widget).getParent().getShell();
        if (widget instanceof  DragSource)
            return ((DragSource) widget).getControl().getShell();
        if (widget instanceof  DropTarget)
            return ((DropTarget) widget).getControl().getShell();
        if (widget instanceof  Menu)
            return ((Menu) widget).getParent().getShell();
        if (widget instanceof  ScrollBar)
            return ((ScrollBar) widget).getParent().getShell();

        return null;
    }

    /**
     * Returns a width hint for a button control.
     * @param button the button
     * @return the width hint
     */
    public static int getButtonWidthHint(Button button) {
        button.setFont(JFaceResources.getDialogFont());
        PixelConverter converter = new PixelConverter(button);
        int widthHint = converter
                .convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
        return Math.max(widthHint, button.computeSize(SWT.DEFAULT,
                SWT.DEFAULT, true).x);
    }

    /**
     * Sets width and height hint for the button control.
     * <b>Note:</b> This is a NOP if the button's layout data is not
     * an instance of <code>GridData</code>.
     *
     * @param button	the button for which to set the dimension hint
     */
    public static void setButtonDimensionHint(Button button) {
        Assert.isNotNull(button);
        Object gd = button.getLayoutData();
        if (gd instanceof  GridData) {
            ((GridData) gd).widthHint = getButtonWidthHint(button);
            ((GridData) gd).horizontalAlignment = GridData.FILL;
        }
    }

    public static int getTableHeightHint(Table table, int rows) {
        if (table.getFont().equals(JFaceResources.getDefaultFont()))
            table.setFont(JFaceResources.getDialogFont());
        int result = table.getItemHeight() * rows
                + table.getHeaderHeight();
        if (table.getLinesVisible())
            result += table.getGridLineWidth() * (rows - 1);
        return result;
    }

    /**
     * Adds an accessibility listener returning the given fixed name.
     *
     * @param control the control to add the accessibility support to
     * @param text the name
     */
    public static void setAccessibilityText(Control control,
            final String text) {
        control.getAccessible().addAccessibleListener(
                new AccessibleAdapter() {
                    public void getName(AccessibleEvent e) {
                        e.result = text;
                    }
                });
    }

    /**
     * Sets the default visible item count for {@link Combo}s.
     * Workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=7845 .
     *
     * @param combo the combo
     *
     * @see Combo#setVisibleItemCount(int)
     * @see #COMBO_VISIBLE_ITEM_COUNT
     *
     * @since 3.5
     */
    public static void setDefaultVisibleItemCount(Combo combo) {
        combo.setVisibleItemCount(COMBO_VISIBLE_ITEM_COUNT);
    }

    public static GridLayout newLayoutNoMargins(int columns) {
        GridLayout layout = new GridLayout(columns, false);
        layout.marginWidth = 0;
        layout.marginHeight = 0;
        return layout;
    }

}
